tions, viz, on the Hagerstown and Harper's Ferry roads. Fitz. Lee, with four regiments of cavalry and six pieces of artillery, left New Market yesterday for Liberty. They are being followed by burnside's cavalry.

GEO. B. McCLELLAN,

Major-General, Commanding.

WAR DEPARTMENT,

Washington, September 12, 1862-1.45 p. m.

Major-General McCLELLAN,

Middlebrook, Md.:

General Porter's corps took up its march this morning. On full consultation with him, it was deemed best to keep his corps together, and to march it by the Leesborough road. In this we were all agreed. Have you any reliable information of enemy's force south of the Potomac? Is it not possible to open communication with Harper's Ferry, so that Colonel Miles' forces can co-operate with you?

H. W. HALLECK,

General-in-Chief.

HEADQUARTERS ARMY OF THE POTOMAC,
Near Urbana, Md., September 12,, 1862-5.30 p. m.

(Received 4.20 a. m., 13th)

Major-General HALLECK:

I have just learned, by signal from Sugar Loaf Mountain, that our troops are entering Frederick. The remainder of Burnside's troops are between Frederick and New Market. Sumner is near Urbana, with our advance guard thrown out to the Monocacy; Williams on his right; Franklin on his left; Couch at Barnesville. Cavalry has been sent toward point of Rocks to ascertain whether there is any force of the enemy in that direction. Burnside has cavalry in pursuit of Fitzhugh Lee, toward Westminster. Should the enemy go toward Pennsylvania I shall follow him. Should he attempt to recross the Potomac I shall endeavor to cut off his retreat. Mo movements to-morrow will be dependent upon information to be received during the night. The troops have marched to-day as far as it was possible and proper for them to move.

GEO. B. McCLELLAN,

Major-General, Commanding.

P. S.- I have ordered Banks to send Eight New regiments to relieve parts of Couch's command left at Offutt's Cross-Roads, Seneca, and Conrad's and Edwards Ferries. How soon may I expect these troops? Their presence at the points indicated is very necessary.

HEADQUARTERS ARMY OF THE POTOMAC,
Near Urbana, Md., September 12, 1862-6 p. m.

(Received 4.08 a. m., 13th)

Major-General HALLECK:

I learn nothing reliable as to the enemy south of the Potomac. I this morning ordered cavalry to endeavor to open communication with Har-